We plan to assess the prevalence of carotid artery disease in a healthy population of 200 elderly adults with isolated systolic hypertension and 200 normotensive controls matched for age and sex. Carotid disease will be assessed by duplex scanning, a noninvasive technique that combines real time B-mode ultrasound with Doppler ultrasound, producing a system capable of both vessel imaging and analysis of blood flow characteristics. Other evaluations to be done include ankle systolic blood pressure measurements to detect lower extremity arterial disease, complete history and physical examination, EKG, blood lipoprotein levels, fasting insulin and glucose levels, hemoglobin, and hematocrit. We will thus be able to evaluate the effect of various risk factors on the development of carotid atherosclerosis. We will also be able to evaluate the relationship between carotid atherosclerosis and atherosclerotic disease of the lower extremities. The first 6 months of the study will consist of preparation and further reproducibility testing of duplex scan measurements. During the following 3 years, duplex scans as well as other evaluations will be completed on all 400 participants. During the final half of the fourth year, the first 100 duplex scans of hypertensive participants will be repeated. These repeat scans will be evaluated to determine whether our methodology can detect carotid disease progression. The final year of the study will consist of data analysis and preparation of final manuscripts.